Stack Exchange

David E Speyer

Ann Arbor, MI

http://www.math.lsa.umich.edu/~speyer

Professor of Mathematics at the University of Michigan. My research interests are in combinatorial algebraic geometry, particularly Schubert calculus, matroids and cluster algebras. I also enjoy thinking about number theory and computational mathematics. Disclaimer: I will often ignore messages about old Stack Exchange posts when I am working on other things.

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Top Questions
115 votes

How did Cole factor $2^{67}-1$ in 1903?

nt.number-theory ho.history-overview prime-numbers factorization asked May 22, 2015 at 15:33
mathoverflow.net

73 votes

What is Lagrange Inversion good for?

mathematics-education co.combinatorics generating-functions asked Jul 16, 2010 at 1:25
mathoverflow.net

63 votes

Is there a "Basic Number Theory" for elliptic curves?

nt.number-theory elliptic-curves zeta-functions birch-swinnerton-dyer asked Jul 31, 2011 at 15:15
mathoverflow.net

62 votes

Can squares of infinite area always cover a unit square?

real-analysis geometry tiling asked Dec 20, 2017 at 22:41
math.stackexchange.com

50 votes

Why does $d^n \exp(-x-x^{-1})/(dx)^n$ only have $n$ positive real zeroes?

ca.analysis-and-odes real-analysis polynomials asked Aug 19, 2015 at 15:45
mathoverflow.net

41 votes

Using Discord to support online teaching

mathematics online-learning asked Mar 13, 2020 at 16:20
academia.stackexchange.com

40 votes

How to compute rational or integer points on elliptic curves

reference-request diophantine-equations math-software elliptic-curves faq asked Sep 27, 2012 at 14:42
math.stackexchange.com

35 votes

Uninsulting way to say "this will eventually be easy"

proofs language-use asked Mar 28, 2015 at 16:30
matheducators.stackexchange.com

35 votes

Is it consistent with ZF that $V \to V^{\ast \ast}$ is always an isomorphism?

fa.functional-analysis linear-algebra set-theory teaching asked Jan 11, 2018 at 14:29
mathoverflow.net

33 votes

Can assignment solve stable marriage?

co.combinatorics algorithms graph-theory asked Nov 12, 2010 at 15:04
mathoverflow.net

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Top Answers
200
Evaluate $\int_0^1 \frac{\log \left( 1+x^{2+\sqrt{3}}\right)}{1+x}\mathrm dx$
math.stackexchange.com

177
How to find the Galois group of a polynomial?
math.stackexchange.com

166
Most memorable titles
mathoverflow.net

128
Why do primes dislike dividing the sum of all the preceding primes?
mathoverflow.net

109
Invertible matrices of natural numbers are permutations... why?
mathoverflow.net

101
Convergence of $\sqrt{n}x_{n}$ where $x_{n+1} = \sin(x_{n})$
math.stackexchange.com

100
Irreducibility of polynomials in two variables
mathoverflow.net

98
Advantages of Mathematics competition/olympiad students in Mathematical Research
math.stackexchange.com

87
$\prod_{n=1}^{\infty} n^{\mu(n)}=\frac{1}{4 \pi ^2}$
mathoverflow.net

86
The Basel problem
math.stackexchange.com

83
What are the most common pitfalls awaiting new users?
mathematica.stackexchange.com

82
Why could Mertens not prove the prime number theorem?
mathoverflow.net

76
Conceptual reason why the sign of a permutation is well-defined?
mathoverflow.net

75
Is it morally right and pedagogically right to google answers to homework?
math.stackexchange.com

72
Applications of the Chinese remainder theorem
mathoverflow.net

71
Open problems with monetary rewards
mathoverflow.net

69
When is the product of two ideals equal to their intersection?
mathoverflow.net

69
Ideas for introducing Galois theory to advanced high school students
mathoverflow.net

69
Generating a finite group from elements in each conjugacy class
mathoverflow.net

68
When can one continuously prescribe a unit vector orthogonal to a given orthonormal system?
mathoverflow.net

64
Strengthening the induction hypothesis
mathoverflow.net

63
Evaluating the integral $\int_0^\infty \frac{\sin x} x \,\mathrm dx = \frac \pi 2$?
math.stackexchange.com

60
Convergence of $\sum \limits_{n=1}^{\infty}\sin(n^k)/n$
math.stackexchange.com

60
Computing $\prod_p(\frac{p^2-1}{p^2+1})$ without the zeta function?
mathoverflow.net

58
Applications of the Chinese remainder theorem
mathoverflow.net

57
English reference for a result of Kronecker?
mathoverflow.net

57
Eigenvalues of matrix sums
mathoverflow.net

56
Striking applications of integration by parts
math.stackexchange.com

56
What should be learned in a first serious schemes course?
mathoverflow.net

55
Are there infinitely many integer-valued polynomials dominated by $1.9^n$ on all of $\mathbb{N}$?
mathoverflow.net

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